Other Income, Net - Additional Information (Detail) $ in Thousands		3 Months Ended					12 Months Ended
	May 30, 2018 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Mar. 31, 2018 USD ($) Parcel	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Disclosure Other Income Net Additional Information Detail [Line Items]
Dividends and interest income							$ 10,900	$ 26,100	$ 29,400
Gain on securities transaction recognized							300	12,400	100
Insurance recoveries				$ 7,700			7,700	1,300	400
Number of land parcels | Parcel						2
Net proceeds							4,600	19,500
Pre-tax gain on sale of land						$ 11,900
Gain on sale of business			$ 3,000				3,000	58,400
Kronos Worldwide, Inc.
Disclosure Other Income Net Additional Information Detail [Line Items]
Gain on insurance settlement related to property damage claim		$ 2,600
Tremont
Disclosure Other Income Net Additional Information Detail [Line Items]
Net proceeds						18,900
Tremont | Promissory Note
Disclosure Other Income Net Additional Information Detail [Line Items]
Principal payment of debt						$ 2,200	7,400	3,700
Amalgamated Sugar Company LLC
Disclosure Other Income Net Additional Information Detail [Line Items]
Dividends and interest income								16,900	$ 25,400
Snake River
Disclosure Other Income Net Additional Information Detail [Line Items]
Gain on securities transaction recognized	$ 12,500				$ 12,500			12,500
NL
Disclosure Other Income Net Additional Information Detail [Line Items]
Insurance recoveries							$ 5,100
Net proceeds			4,600					$ 600
Pre-tax gain on sale of land			$ 4,400
NL | Insurance and Risk Management Business
Disclosure Other Income Net Additional Information Detail [Line Items]
Proceeds from sale of business		3,250
Gain on sale of business		$ 3,000